Iran's ambassador to the International Atomic Energy Agency, Reza Najafi, attends a meeting of the IAEA Board of Governors in Vienna on Sept. 9, 2013. / Georg Hochmuth, epa

by Michele Chabin, Special for USA TODAY

by Michele Chabin, Special for USA TODAY

JERUSALEM - Israelis were unsettled Wednesday by the news that the United States had not yet decided whether to strike Syria over its chemical weapons, and that Russia was restoring plans to help archenemy Iran get missiles and another nuclear facility.

Members of the Israeli government who were contacted about the development would not talk about it. Efraim Karsh, a professor of Middle Eastern Studies at Kings College, London, said this was bound to happen given President Obama's perceived withdrawal from Middle Eastern affairs overall.

"Russia has always been a Middle Eastern power ... So they're going to be involved," said Karsh, a senior research associate at the BESA Institute, a think tank in Jerusalem.

"Obama is viewed in the Middle East as a weak president and this is an opportunity for Russia to reassert some of its influence at the West's expense."

Russia will supply Iran with a modified version of the sophisticated S-300 anti-aircraft system and build a new nuclear reactor for the regime, the Russian daily Kommersant business newspaper reported Wednesday according to the Associated Press.

The news comes a day after Obama said he was mulling a proposal by Russian President Vladimir Putin to persuade Syria to turn over its chemical weapons to inspection. Obama has threatened to hit Syria militarily for using chemical weapons in an August attack against a rebel stronghold that killed 1,400 people.

Israel has been watching events unfold because Syria has threatened to attack the Jewish state if the U.S. attacks Syria. And Iran is rebuffing pressure from the United States to end a nuclear program that is suspected of building an atomic bomb.

Iran's leaders have said in the past that Israel needs to be eliminated, and Israel believes the nuclear program must be destroyed militarily if Iran refuses to shut it down. Russian assistance to Iran in setting up better air defenses may make it more difficult for an attack on Iran's nuclear facilities.

On the Russian idea for Syria, Israeli President Shimon Peres said that the Syrians cannot be trusted to follow through.

Kommersant reported that the deal between Moscow and Tehran was formulated as part of Russia and Iran's "commonality of views on the situation in Syria."

Russia has helped Iran repair and complete a reactor in Bushehr. Russian media said Putin will discuss details this Friday on another reactor and the missile defense system during his first meeting with Iranian President Hassan Rouhani in Bishkek, Kyrgystan.

Russia on Wednesday said it will supply Iran with five battalions of the S-300VM Antey-2500 system, a modified export version of the S-300V originally ordered by Iran. Former Russian president Dmitry Medvedev canceled the original contract in 2010 under pressure from the U.S. and Israel.

A security policy expert told the Kommersant that the anti-aircraft batteries Russia would provide were even better than the ones Iran originally bought.

Putin's press secretary Dmitry Peskov said the agenda of the Russian president's talks had not been announced, although he confirmed that nuclear energy and the Bushehr nuclear power plant were some of the topics up for discussion.

"They will discuss cooperation in the atomic energy sector, including in the context of the Bushehr nuclear power plant. The subject cannot be avoided," he said. "The issue of military-technical cooperation is also on the agenda

Karsh said that "generally speaking" Russia does not seek a military confrontation in the region.

"Exercising influence in Syria is a way for Russia, which used to have strong footholds in Iraq and Egypt, to get back into the game," he said. "It wants to score points, to show it's important."

Karsh says Russia has good relations with Israel, but that can change.

"It's a delicate game that Russia is playing, a balancing act (to support) Syria while not antagonizing Israel too much. Hopefully the strategy won't explode."

Israel's Chanel 10 News anchor Gil Tamari theorized that Obama is relieved by the role Putin is playing.

"I think he's happy that Putin and the Russians have filled the (leadership) vacuum.," he said. "He's very happy that someone else is doing the work for him and has brought a compromise to the table."